1. Field of the Invention
The present invention relates to an electrophotographic photosensitive member and to a process cartridge and an electrophotographic apparatus each including the electrophotographic photosensitive member.
2. Description of the Related Art
One example of an electrophotographic photosensitive member installed in an electrophotographic apparatus is an organic electrophotographic photosensitive member containing an organic photoconductive substance (charge generating substance) (hereinafter referred to simply as an “electrophotographic photosensitive member”). Electrophotographic photosensitive members have been widely studied. In recent years, for the purpose of extending the life of an electrophotographic photosensitive member and improving image quality, it has been desired to improve image deletion in response to an improvement in the mechanical durability (abrasion resistance) of the electrophotographic photosensitive member.
Image deletion is a phenomenon in which a blurred electrostatic latent image results in a blurred output image. It is believed that the reason for image deletion is that discharge products resulting from charging remaining on the surface of an electrophotographic photosensitive member change the characteristics of the constituent materials of the surface of the electrophotographic photosensitive member.
Image deletion may be reduced by using an electrophotographic photosensitive member that contains an additive agent. Japanese Patent Laid-Open No. 2007-279678 proposes a method for preventing image deletion by providing a surface layer containing a curable resin of an electrophotographic photosensitive member with a particular amine compound. Japanese Patent Laid-Open No. 63-097959 proposes the addition of a urea compound to a photosensitive layer to prevent deterioration of an electrophotographic photosensitive member caused by an active gas.
However, the present inventors found that the amine compound described in Japanese Patent Laid-Open No. 2007-279678 tends to reduce the electric potential stability of the electrophotographic photosensitive member and has an insufficient image deletion preventing effect. The urea compound described in Japanese Patent Laid-Open No. 63-097959 has an insufficient image deletion preventing effect and tends to decrease electric potential stability.